A system is the most productive thing that can be in any activity. It is enough to remember lessons of music or foreign languages when all skills are lost if they are not practiced systematically. The same can be said of medicine. If you drink tablets once it will not give any effect.
It is not surprising that the same statement concerns SPA procedures which require a systematic approach for a proper effect. One-time going to a SPA salon does not give ant result and will be similar to usual wasting money. Changes in the body can occur for a long period and if one stop effecting it all actions will be useless.
Specialists of SPA procedures understood it long ago and developed special SPA programs that are meant not for a one-time procedure but for a systematic improvement of the body state.
This could be one SPA procedure that is repeated over a long period of time or a range of various procedures aimed at achieving a particular result. One should not regard such programs as pumping out money. SPA industry is not a magician and can not satisfy all desires of a client with the click of fingers.